Motor bucking redux

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DaveC426913
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Motor bucking redux

Post by DaveC426913 » Mon Oct 29, 2018 8:34 pm

Still having this problem.

In reverse, at anything other than dead slow, my motor bucks - it tries to kick up. Bang ... bang ... bang.

It is particularly frustrating, since, if I reduce throttle to stop the bucking, it slips out of gear and starts to grind gears.

Now, I can fix the latter problem (in theory, at least. I've tried to adjust the cable to find a balance between grinding in reverse and grinding in forward. I will have to get them to do it in the shop).

I'm concerned about why it's bucking.

It's a Honda BF50.

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Don T
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Re: Motor bucking redux

Post by Don T » Mon Oct 29, 2018 8:45 pm

Hello,
Depends on what you mean by "bucking."
Could be that the reverse lock is not working and the motor is lifting itself, cavitating then dropping back down (rinse & repeat). When you shift it into reverse a lever should lock the motor in the down position via the transom angle setting rod. Could just be corroded and need some lube and breaking loose. See page 21 of the owners manual.

K9Kampers
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Re: Motor bucking redux

Post by K9Kampers » Mon Oct 29, 2018 9:00 pm

Disconnect the cable from the motor lever, shift FNR as motor lever allows. If problem disappears, adjust or replace shift cable, if problem persists, explore shifting mechanism on motor.

DaveC426913
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Re: Motor bucking redux

Post by DaveC426913 » Mon Oct 29, 2018 10:11 pm

Don T wrote:Hello,
Depends on what you mean by "bucking."
Could be that the reverse lock is not working and the motor is lifting itself, cavitating then dropping back down (rinse & repeat). When you shift it into reverse a lever should lock the motor in the down position via the transom angle setting rod. Could just be corroded and need some lube and breaking loose. See page 21 of the owners manual.
That sounds pretty plausible.
I'll check that out.

Does that lever have to self-disengage in order to raise the motor?

i.e. I raise and lower my motor every sail. If it needs to re-engage every time I lower the motor, then that would make sense if it's not operating properly.

Do you mean this manual?
https://cdn.powerequipment.honda.com/ma ... ZW4604.pdf
p21 is about the remote control and choke.

I'm assuming this lock is on the transom (not the remote control).

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Don T
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Re: Motor bucking redux

Post by Don T » Mon Nov 19, 2018 8:30 pm

Hello,
Yes the lock mechanism should lock in reverse and unlock in forward so the motor can kick up if you hit something. I believe the lock mechanism is independent of the hydraulic lift system, although, the lock should be on the part of the engine that raises with the ram. I'm just pulling from memory here so the manual is your best resource.

Jumping in and out of reverse gear is also a possibility as someone else commented. Video w/ audio of it doing the "buck" would help us to help you make a diagnosis.

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Re: Motor bucking redux

Post by DaveC426913 » Mon Nov 19, 2018 10:36 pm

Don T wrote:Hello,
Yes the lock mechanism should lock in reverse and unlock in forward so the motor can kick up if you hit something. I believe the lock mechanism is independent of the hydraulic lift system, although, the lock should be on the part of the engine that raises with the ram. I'm just pulling from memory here so the manual is your best resource.

Jumping in and out of reverse gear is also a possibility as someone else commented. Video w/ audio of it doing the "buck" would help us to help you make a diagnosis.
No, it's not jumping out of gear. That's what happens if I don't give it enough throttle. This happens when I give it too much.

I'm pretty certain now it's the anti-kick lock, even though I don't yet know what it looks like. I'll check the manual.


It occurs to me that part of the problem is that the gear shifter does not engage sufficiently at low throttle. It grinds the gears. But adjusting it just means it'll just grind that in Fwd gear instead.
Since throttle and gear shift are separate cables, it might help a little if the gear shift cable wheel in the housing had a fractionally larger radius. That would result in slightly more "gear shiftiness" for a given amount of "throttliness". Maybe just a bit of plastic or metal on the wheel under the cable to enlarge the radius a millimeter or two.

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Re: Motor bucking redux

Post by K9Kampers » Tue Nov 20, 2018 2:54 am

DaveC426913 wrote: I'm pretty certain now it's the anti-kick lock, even though I don't yet know what it looks like. I'll check the manual.
On your OB manual link, page 25 -Tilt Lever. Lever in the FREE position allows OB to tilt up. Lever must be in the LOCK position when operating in reverse. As mentioned, a corroded or stuck mechanism could be the issue.
DaveC426913 wrote: It occurs to me that part of the problem is that the gear shifter does not engage sufficiently ... / / ...it might help a little if the gear shift cable wheel in the housing had a fractionally larger radius. That would result in slightly more "gear shiftiness" for a given amount of "throttliness". Maybe just a bit of plastic or metal on the wheel under the cable to enlarge the radius a millimeter or two.
Proper adjustment for shifting action does not require a bit of plastic on the wheel or whatever to fudge it into place! Shifting into F-N-R should be a definate click without a bit of grinding.

Control cables can wear, stretch, corrode, stick, pinch, break,...and can result in what you are experiencing. Trying to adjust a bad cable is a tail-chasing waste of time! There could also be something happening on the OB with the shift rod, clutch dog, thrust bearing, etc...

Disconnecting the shift cable at the OB and shifting the mechanism manually will allow you to discern between the two. If the symptoms disappear, then the problem is with either the shift cable or the shift control at helm. If the symptoms continue, then the problem is with the shift mechanism in the gear housing.

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Re: Motor bucking redux

Post by DaveC426913 » Tue Nov 20, 2018 9:08 pm


Proper adjustment for shifting action does not require a bit of plastic on the wheel or whatever to fudge it into place! Shifting into F-N-R should be a definate click without a bit of grinding.

Control cables can wear, stretch, corrode, stick, pinch, break,...and can result in what you are experiencing. Trying to adjust a bad cable is a tail-chasing waste of time! There could also be something happening on the OB with the shift rod, clutch dog, thrust bearing, etc...

Disconnecting the shift cable at the OB and shifting the mechanism manually will allow you to discern between the two. If the symptoms disappear, then the problem is with either the shift cable or the shift control at helm. If the symptoms continue, then the problem is with the shift mechanism in the gear housing.
Yes. I've replaced the cables twice. And have adjusted them as best I can. A few mm one way and it grinds into R; a few the other way and it grinds into D.
I may have to take the whole thing in to the shop just to get it adjusted by a pro...

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Re: Motor bucking redux

Post by K9Kampers » Wed Nov 21, 2018 9:00 am

Does the grinding occur just at the instance of gear engagement during shifting and then ceases...

or

does the grinding continue after shifting for a few seconds, then ceases...

or

is the grinding always audible while in gear after shifting?

K9Kampers
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Re: Motor bucking redux

Post by K9Kampers » Wed Nov 21, 2018 9:18 am

Also, when shifting at the control box, are you easing slowly into gear or is it a quick action?

DaveC426913
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Re: Motor bucking redux

Post by DaveC426913 » Wed Nov 21, 2018 4:06 pm

K9Kampers wrote:Does the grinding occur just at the instance of gear engagement during shifting and then ceases...
or
does the grinding continue after shifting for a few seconds, then ceases...
or
is the grinding always audible while in gear after shifting?
If I ease it into low throttle, it will grind until fully engaged then stop grinding.
If I shift it into gear with conviction, then it does not grind at all.

Once I get the reverse lock fixed, this whole throttle thing should stop being a problem, since then I can throw it into reverse with impunity.

K9Kampers wrote:Also, when shifting at the control box, are you easing slowly into gear or is it a quick action?
It has to be quick.
Putting it into gear slowly will give every boat-owner within earshot the screamin' heebie-jeebies with the drawn-out sound of grinding gears.

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Re: Motor bucking redux

Post by K9Kampers » Wed Nov 21, 2018 6:44 pm

Once I get the reverse lock fixed,...
Your assessment is sound - correct the reverse lock issue first before diagnosing / fiddling with other symptoms that may be the result of the first problem.

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